<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>element属性</title>
</head>
<body>
    <img id='app' class="main" src="./document_attribute.html" alt="图片不见了">
</body>
<script>
    var d = document.getElementById('app')

    console.log(d.id);
    console.log(d.className);
    console.log(d.src);
    console.log(d.alt);
</script>
</html>